The invention discloses a robot mobile device. According to the key point of the technical scheme, the robot mobile device comprises a main body bracket and walking assemblies, wherein a transmissionshaft and a first motor are arranged on the main body bracket, and first gears are fixedly connected to the both ends of the transmission shaft; the walking assemblies comprise supporting plates and base plates, second gears are arranged on the supporting plates, and first hinged rods are arranged between the first gears and the second gears to keep the two gears engaged; the second gears on the two supporting plates are arranged in a staggered mode in the circumferential direction of the transmission shaft, and second hinged rods are arranged between the supporting plates and the main body bracket; a plurality of rotating shafts are arranged on the lower surface of the base plates, the length directions of the rotating shafts are all perpendicular to the advancing direction of the main body bracket, and the rotating shafts are fixedly connected with rollers; a third motor is further arranged on each base plate, the rotating shafts are driven by first synchronous driving belts. The robot mobile device can not only drive the robot to move quickly and stably on the level road section, but also drive the robot to move on the step rod section or the road section with obstacles.